The invention relates to a pneumatic spring device for a motor vehicle.
A generic pneumatic spring device includes a generally known pneumatic spring which includes a rolling piston, a pneumatic spring cover which is moveable in axial relation to the rolling piston, and an interposed elastomer bellows configured as a rolling bellows with trapped compressible air volume. The spring action of such a pneumatic spring is based on the compression of air in the trapped air volume, with the air volume decreasing during spring compression as the rolling bellows rolls off. As a result, the air pressure rises in the air volume, resulting in a spring force in combination with the effective area of the pneumatic spring.
Such a pneumatic spring is disadvantageous because it normally exhibits a firm behavior of the spring characteristic at small amplitudes of greater excitation frequency. This behavior is also described as harshness. Moreover, rolling bellows in such pneumatic springs normally involve so-called transverse bellows, which have a natural torsion leading to a torsion moment in the pneumatic spring. This torsional moment has an adverse effect on the axle as additional resistance in opposition to the spring compression. This results in a reduction in comfort in such air-sprung vehicles.
Further, a spring device of a chassis is known with a combination of a spring element and a position control, wherein a shock absorber can be omitted (DE 10 2004 010 301 A1). Particular properties of the afore-described generic pneumatic spring device are not indicated here.